ruby_require_auth.rb

#!/usr/bin/env ruby
require 'rubygems'
require 'json'

class AuthenticationException < StandardError ; end

module RequireAuth
        def requireauth ( *args )
                args.each do |field|
                        old_method = instance_method(field)

                        puts "rebind stuff"
                        define_method( field ) { |*varg|
                                jsonstr = *varg.first
                                j = JSON.parse( jsonstr )
                                raise AuthenticationException, "Not Authenticated" if j["authenticated"] < 1
                                old_method.bind(self).call(*varg)
                        }
                end
        end
end

class Foo
        extend RequireAuth

        def bar( json )
                puts "This is bar"
        end

        requireauth :bar
end

jsonstr = '{ "foo": "bar", "authenticated": 0 }'

fb = Foo.new
fb.bar( jsonstr )